This invention relates to engines, and more particularly, to engine parts and a process for making the same.
Traditionally, engines have been made of metal, usually steel or cast iron. Steel and cast iron engines are useful, except they are quite heavy and consume considerable amounts of gasoline or diesel fuel. Conventional engines exert large compressive forces, considerable torque, and substantial secondary harmonic vibrations which have to be dampened by counterbalancing pistons, flywheels, dampeners, etc. The moving metal parts of cast iron and steel engines generate high centrifugal reciprocating, and inertial forces, momentum, and loads. Generally, the weight of the engine adversely affects its performance, efficiency, and power.
Recently, it has been suggested to use plastic engine parts in automotive engines. Such suggestions have appeared in the December 1980 issue of Automotive Industries at pages 40-43, in an article entitled, "What . . . a Plastic Engine? "; in the May 8, 1980 issue of Machine Design, Volume 52, No. 10, in an article entitled "Plastic Engine Is Off And Running"; in the September 1982 issue of Popular Science at page 71 in an article entitled "Ford's Impossible Plastic Engine"; in the Feb. 20, 1984 issue of Design News at page 46 in an article entitled, "Plastic Engine Parts Cut Total Engine Weight in Half"; in the May 6, 1985 issue of Design News at page 62 in an article entitled, "Applying the Plastic Engine and in French Application No. 2,484,042, published Dec. 11, 1981."
An experimental prototype engine with concealed plastic engine parts was displayed at the Society of Automotive Engineers' (SAE) Show in Detroit, Mich. in February 1980.
Over the years, amide-imide polymers have been developed for use in molding and producing various products, such as wire coatings, enamels, films, impregnating materials, and cooking utensils. Typifying these prior art amide-imide products, polymers and molding processes are those described in U.S. Pat. Nos. 3,546,152; 3,573,260; 3,582,248; 3,660,193; 3,748,304; 3,753,998; 4,016,140; 4,084,144; 4,136,085; 4,186,236; 4,167,620; and 4,224,214. These prior art products, polymers, and molding processes have met with varying degrees of success.
It is, therefore, desirable to provide a lightweight engine part. Amide-imide polymers have been developed for improved lightweight composite engine parts such as:
a wrist pin, U.S. Pat. No. 4,430,906; PA1 a timing gear, U.S. Pat. No. 4,433,964; PA1 a rocker arm, U.S. Pat. No. 4,430,969; PA1 a piston ring, U.S. Pat. No. 4,432,925; PA1 a valve, U.S. Pat. No. 4,433,652; PA1 a tappet, U.S. Pat. No. 4,430,970; PA1 a valve spring retainer, U.S. Pat. No. 4,432,311; PA1 a piston, U.S. Pat. No. 4,440,069; PA1 a push rod, U.S. Pat. No. 4,453,505; and PA1 a connecting rod, U.S. Pat. No. 4,458,555.